Spiderinabox provides an out-of-the-box solution for secure browsing on Mac systems. It includes a basic preconfigured installation of OpenBSD prepared as a VirtualBox image loaded with Firefox and a few scripts and programs to launch it and invoke Firefox over a secure connection. The visualization of Firefox is done on the OS X side using XQuartz, so you don't need to exit your working environment and switch between OS X and OpenBSD. Firefox runs encapsulated in OpenBSD and doesn't have access to OS X in any way.

For Human Eyes Only is a Firefox plugin that lets you post in a way that prevents computers from analyzing your messages. The plugin converts your messages into images in a way that makes it hard for computers to extract your message, while genuine humans can still read it.

FirefoxSync for DolphinHD is a plugin for DolphinHD to keep information such as passwords, bookmarks, tabs, and history synchronized between you desktop Web browser and you mobile Web browser by using Mozilla Weave/Firefox Sync. It lets you access open tabs from the desktop on Dolphin and the other way around. It is not produced by the Mozilla Foundation.

CreditCardNanny is a Web browser extension for Google Chrome and Mozilla Firefox that detects forms that otherwise look secure (with a proper and valid SSL certificate, encrypted, and seemingly safe to enter sensitive data such as credit card details) but actually then submit this form data in a cleartext email to the site administrators. This extension detects such forms and warns you of the possibility that sensitive information may be exposed in clear-text, putting you and your sensitive data at risk. You can test the extension by browsing to https://cc-nanny.appspot.com/test-secure-page, a dummy credit card form that uses a form emailer script, a very common pattern used on an alarmingly large number of Web sites.

WMS Inspector is a Firefox add-on with tools for working with Web Map Services (WMS). It can be especially useful when working with JavaScript mapping libraries like OpenLayers or MapBender or setting up WMS services with servers like MapServer, GeoServer, or deegree. Its main features include structured loading of all WMS requests in the current page and its parameters, sorted by service or type, individual WMS request (images or errors) visualization on a lateral pane, the ability to copy services, requests, or parameters to the clipboard, direct editing of request parameter values, and output of GetCapabilities requests as an HTML report or the original file.

django-weave is a Firefox Weave server. Weave is a free browser add-on from Mozilla Labs that keeps your bookmarks, saved passwords, browsing history, and open tabs backed up and synchronized, with end-to-end encryption for your privacy and security.

After the Deadline checks English spelling, misused words, style, and grammar using artificial intelligence and natural language processing. This add-on adds After the Deadline's smart technology to the Firefox browser. Now you can check grammar in your online word processor, spell check your Web mail, and send tweets with confidence.

iMacros for Chrome is an extension that allows you to automate repetitive tasks like visiting the same sites every day, filling out forms, and remembering passwords. It can automatically fill Web forms that stretch over several pages. It can automate the download and upload of images, files, or entire pages (with or without images). iMacros includes a user agent switcher, functions to download PDF and Flash, and ad-blocking and image-blocking functions. iMacros can automatically read data from a Web site and export it to CSV files. You can use this feature to download stock quotes, gather and compare Web store prices, and more. Web professionals can use iMacros for functional, performance, and regression testing of Web applications.

Ymacs is an extensible AJAX text editor aimed for programmers. It's similar in spirit, features, and key bindings to Emacs: it supports multiple buffers, split frames, dynamic completion, multiple keymaps, and Emacs-like undo queue and kill ring. And of course, Emacs-like key bindings for all of that. It provides syntax highlighting and automatic indentation for a few programming modes, currently JavaScript, XML, CSS, and Lisp. Ymacs is based on the DynarchLIB AJAX toolkit and currently runs on Firefox (support for more browsers is planned). It's implemented in JavaScript and can be programmed in JavaScript as it's running.

Peerscape is an experimental peer-to-peer social network implemented as an extension to the Firefox web browser. It implements a kind of serverless read-write web supporting third-party AJAX application development.